Fb-6 Surface Tension of Aqueous Solutions
Aim
To demonstrate that in general organic substances dissolved in water lower the surface tension.
Apparatus
- Camphor
- Overhead projector
- Petrie dish, water
- Razor blade
Camphor Boat and Diagram.
Description
If a piece of camphor is scraped into a dish full of water it will dart over the surface in a seemingly random manner.
Camphor is only slightly soluble in water. On an uneven piece of camphor, solution occurs more rapidly at a point P than where the surface is smooth. The strength of the camphor-water solution near P is greater than at any other point and hence the surface tension is least at P. Therefore the greater tensions on the other side pull the camphor away from P.